Keys and Rooms Python Solution with Tests

lcpy gen -n 841   # by problem number
lcpy gen -s keys_and_rooms   # by problem name

Input: rooms = [[1],[2],[3],[]]
Output: true
Explanation:
We visit room 0 and pick up key 1.
We then visit room 1 and pick up key 2.
We then visit room 2 and pick up key 3.
We then visit room 3.
Since we were able to visit every room, we return true.

Input: rooms = [[1,3],[3,0,1],[2],[0]]
Output: false
Explanation: We can not enter room number 2 since the only key that unlocks it is in that room.

class Solution:
    # Time: O(n + k) where k is the total number of keys
    # Space: O(n)
    def can_visit_all_rooms(self, rooms: list[list[int]]) -> bool:
        visited = {0}
        stack = [0]
        while stack:
            room = stack.pop()
            for key in rooms[room]:
                if key not in visited:
                    visited.add(key)
                    stack.append(key)
        return len(visited) == len(rooms)